Correct linux-compat sigaltstack implementation.

Helps HotSpot Java VMs a bit, but not totally.  I can at least run javac
on J2SE 1.4beta with good results, but anything that uses swing seems to
fail on something else.

2 files changed, 26 insertions, 11 deletions

diff --git a/sys/compat/linux/linux_signal.c b/sys/compat/linux/linux_signal.c
index 1a0b12f8476..9115dc93393 100644
--- a/sys/compat/linux/linux_signal.c
+++ b/sys/compat/linux/linux_signal.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_signal.c,v 1.10 2001/07/27 06:10:38 csapuntz Exp $	*/
+/*	$OpenBSD: linux_signal.c,v 1.11 2001/08/09 14:15:22 niklas Exp $	*/
 /*	$NetBSD: linux_signal.c,v 1.10 1996/04/04 23:51:36 christos Exp $	*/
 
 /*
@@ -841,16 +841,23 @@ linux_sys_sigaltstack(p, v, retval)
 	caddr_t sg;
 
 	sg = stackgap_init(p->p_emul);
-	bsd_nss = stackgap_alloc(&sg, sizeof *bsd_nss);
 
-	error = copyin(SCARG(uap, nss), &linux_ss, sizeof linux_ss);
-	if (error)
-		return (error);
+	if (SCARG(uap, nss) != NULL) {
+		bsd_nss = stackgap_alloc(&sg, sizeof *bsd_nss);
+
+		error = copyin(SCARG(uap, nss), &linux_ss, sizeof linux_ss);
+		if (error)
+			return (error);
+
+		bsd_nss->ss_sp = linux_ss.ss_sp;
+		bsd_nss->ss_size = linux_ss.ss_size;
+		bsd_nss->ss_flags = (linux_ss.ss_flags & LINUX_SS_DISABLE) ?
+		    SS_DISABLE : 0;
+
+		SCARG(&sa, nss) = bsd_nss;
+	} else
+		SCARG(&sa, nss) = NULL;
 
-	bsd_nss->ss_sp = linux_ss.ss_sp;
-	bsd_nss->ss_size = linux_ss.ss_size;
-	bsd_nss->ss_flags = linux_ss.ss_flags;
-	SCARG(&sa, nss) = bsd_nss;
 	if (SCARG(uap, oss) == NULL) {
 		SCARG(&sa, oss) = NULL;
 		return (sys_sigaltstack(p, &sa, retval));
@@ -863,7 +870,11 @@ linux_sys_sigaltstack(p, v, retval)
 
 	linux_ss.ss_sp = bsd_oss->ss_sp;
 	linux_ss.ss_size = bsd_oss->ss_size;
-	linux_ss.ss_flags = bsd_oss->ss_flags;
+	linux_ss.ss_flags = 0;
+	if (bsd_oss->ss_flags & SS_ONSTACK)
+		linux_ss.ss_flags |= LINUX_SS_ONSTACK;
+	if (bsd_oss->ss_flags & SS_DISABLE)
+		linux_ss.ss_flags |= LINUX_SS_DISABLE;
 	return (copyout(&linux_ss, SCARG(uap, oss), sizeof linux_ss));
 }
 
diff --git a/sys/compat/linux/linux_signal.h b/sys/compat/linux/linux_signal.h
index c968de65efc..29648cd53d6 100644
--- a/sys/compat/linux/linux_signal.h
+++ b/sys/compat/linux/linux_signal.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_signal.h,v 1.6 2001/07/27 06:10:38 csapuntz Exp $	*/
+/*	$OpenBSD: linux_signal.h,v 1.7 2001/08/09 14:15:22 niklas Exp $	*/
 /* 	$NetBSD: linux_signal.h,v 1.4 1995/08/27 20:51:51 fvdl Exp $	*/
 
 /*
@@ -114,6 +114,10 @@ struct linux_sigaltstack {
 	size_t	ss_size;
 };
 
+/* ss_flags */
+#define LINUX_SS_ONSTACK	0x00000001
+#define LINUX_SS_DISABLE	0x00000002
+
 extern int bsd_to_linux_sig[];
 extern int linux_to_bsd_sig[];